Aromatic polyamides, or aramids, are useful for a variety of applications particularly as fibers. Some of these polymers have high strength, modulus, thermal resistance, etc. Thus, aramids with combinations of good physical properties are constantly sought. This usually means making aramids with new combinations of repeat units.
U.S. Pat. No. 4,172,938 is such a typical patent and describes various repeat units which are useful as aramids. The specific aramids disclosed herein are not described.